Table 1 Parameter values employed in simulations

\(b_{{1}}\)

Recruitment rate

57,554 years⁻¹

[55], year 2018

\(b_{{2}}\)

Natural average death rate

1/85 years⁻¹

[55]

β

Transmission rate of symptomatic

1/N(0)

[38], adjusted to provide a basic reproduction number between 5-6

\(\beta _{ar}\)

Specific transmission rate factor of asymptomatic

1

[56, 57]

\(\beta _{hr}\)

Specific transmission rate factor of severe cases (hospitalized)

1/50 (nominal)

Sensitivity analysis for \(\beta _{hr} \in [ 1/10,1/100 ]\)

γ

Average incubation period

1/5.5 days⁻¹

[36]

η

Average immunity loss rate

0

[36, 56]

α

Mortality rate for severe cases associated with disease

12%

[58]

\(\tau _{0}\)

Average immune response rate

1/10 days⁻¹

[36]

\(p_{s}\)

Fraction of slight cases

55%

[58, 59]

\(p_{h}\)

Fraction of severe cases

20%

[58, 59]